Drilling device



5 Sheets-Sheet 1 BY ATTORNEY M. C. HUFF MAN DRILLING DEVICE March 26,1963 Filed OCT.. 28, 1960 March 26, 1963 M. c. HUFFMAN 3,082,741

, DRILLING DEVICE Filed oct. 28, 1960 s sheets-sheet 2 IN VEN TOR.

ME/V/N C. HUFFMAN mm2 @www A TTRNE Y y March 26, 1963 M. c. HUFFMAN3,082,741

DRILLING DEVICE Filed Oct. 28, 1960 5 Sheets-Sheet 3 42 salas 4 IA 9T-lk '|50 5W [II-u [En Q IO 7-l Icy |42 INVENToR.

MERY/N C. HUFFMN BY '(4). M1417/ ATTORNEY 3,082,741 DRILLING DEVICEMervin C. Hudman, Denver, Colo., assigner to Gardner- Denver Company, acorporation of Delaware. Filed (het. 28, 1960, Ser. No. 65,757 3 Claims.(Cl. 12l 7) This invention pertains to fluid operated drilling devicesand, more particularly, to percussive rock drills having independentchuck rotation means.

Drilling devices of the aforedescribed character commonly include ahammer motor comprising a cylinder, a hammer piston and an automaticvalve mechanism for admitting motive duid, such as compressed air, tothe cylinder to produce reciprocation of the hammer within the cylinder.The us-ual reciprooative cycle of the hammer consists of a power strokeand a return stroke. During the power stroke, the hammer typicallyimpacts that portion of a drill rod which is held in the drill chuck. Arapid succession of such hammer blows imparts Aa percussive cuttingaction to a drill bit attached to the end of the rod.

It is known that positive rotation of a drill rod generally increasesthe cutting action of an attached bit and substantially increases therate of penetration of most rock `formations. Therefore, various meanshave been devised to rotate the drill rod chuck member to effect bitrotation. One widely used device for providing chuck rotation is aride-'bar mechanism which operates in response to reciprocation of theaforementioned hammer piston. More particularly, the movable hammercoacts with a ratchet device in a well known manner t rotate the chuckintermittently. However, this interaction of the hammer with the ratchetof a ride-bar mechanism necessarily places a rotational load upon thehariimer, thereby reducing the energy available for impacting the drillrod. Furthermore, in deep hole drilling the rotational drag between thedrill rod andthe wall of the hole may become sufciently great to causesevere reduction in the rate of operation of the drill when thereciprocating drill motor is required to provide rotation as well ashammering. Moreover, hammer motors which employ only rifle-bar devicesto produce chuck rotation provide no selective control over the rate ofbit rotation. It is known, however, that a controllable rate of rotationof the bit is highly desirable for drilling various types of rock. Indrilling soft rock, `for example, light impacting and -fast rotationproduce rapid penetration; while heavy percussion and slow rotation aremore eliiciently employed in hard-rock drilling.

The iabove-enumerated advantages of independent bit rotation are wellknown; and, various devices have been proposed to overcome the statedlimitations of rifle bar mechanisms. Typically, such prior art devicescomprise a iluid actuated rotation motor of the gear or vane typemounted upon the front head or back head portion of the drill Iandsuitably connected by gearing to a rotatable chuck journaled at the`front of the drill. This arrangement overcomes the principaldisadvantages of the riile bar mechanism in that the full impactingforce of the ham-.mer may be delivered to the drill rod. Furthermore,insofar as the rotation motors of prior art devices are independentlycontrollable, the rate of rotation of the bit may be selectively variedwithout a corresponding variation in the rate of operation of the hammermotor. There are, however, certain operational limitations and designdisadvantages connected with conventionally constructed independentrotation devices; `and, it is the broad object of this invention toprovide an improved drilling device which obviates these shortcomings.

ln many conventional drills, including those drills which have arotation motor instead of a rifle-bar de- ,I iidZi-f-il Patented Mar.26, i953 vice, the chuck is not rotated in response to reciprocation ofthe hammer. While elimination of the rifle-bar avoids loss of pistonenergy as aforedescribed, there remains no means for providing hammerrotation relative to the internal wall of the cylinder. Localized wearbetween the relatively movable surfaces of the cylinder and hammer thedrill and air or water is forced through the conduit and the drill rodto the bottom of the drilled hole to liush drill cuttings to thesurface. Usually the conduit coaxially penetrates the cylinder and thehammer piston and is removable therefrom for periodic inspection andcleaning. ln conventional drills having an independent rotation motorsecured to the hammer motor housing, interference with assembly anddisassembly of the fluid conduit by various parts of the rotation motoris usually 'avoided by laterally offsetting the rotation motor withrespect to longitudinal axis of the hammer motor. However, an object ofthis invention is the provision of a substantially alined arrangement ofthe rotation motor and the hammer motor which provides ready access tothe iluid conduit. rIltis object is accomplished by providing a rotarymotor having intermeshing rotors which are mounted in end to endrelationship with the hammer motor, whereby one of the rotors iscoaxially penetrated by the duid conduit. Accordingly, this arrangementprovides compactness, ruggedness and simpliiication of manufactureheretofore unobtainable in independently rotated rock drills.

In many modern rock drilling devices intended to effect deeppenetration, so-called sectional drill rods are employed. Typically, adrill shank is coupled to the uppermost drill rod section of a string,and the shank, in turn, is non-rotatably secured in the rotating chuckportion of the drill. It is desirable that the independent rotationmotor be operationally suited to assist the drill operator in rapidlyconnecting and disconnecting the usual threaded coupling between thedrill rod and the shank. This operational :feature of the drill reducesoperator fatigue and, by decreasing the time required for coupling anduncoupling, decreases the cost o drilling. Therciore, it is an object ofthis invention to provide a reversible rotation motor to aiiord thisimportant advantage.

These and other more specific objects and advantages of the presentinvention will appear upon reading the specification and appended claimsin connection with the attached drawings in which:

FIGURE l is a top plan view of a drilling device constructed inaccordance with the present invention;

FIG. 2 is a longitudinal sectional View taken substantially along lines2 2 of FIG. l;

FlG. 3 is a transverse sectional view taken along lines 3 3 of FiG. 2;

FIG. 4 is a transverse sectional view taken along lines 4 4 of iFIG. v2;

FIG. 5 is a -transverse sectional view taken along lines 5 5 of FIG. 2;

FIG. 6 is a fragmentary sectional view taken substantitally along lines6 6 of FIG. 5;

FIG. 7 is a transverse sectional View taken along lines 7 7 of FIG. 2;

FIG. 8 is an enlarged transverse section view taken along lines 8-8 ofFIG. 2;

FIG. 9 is a fragmentary sectional view taken along lines 9 9 of FIG. 8;

FIG. l is a fragmentary sectional View taken along lines 1G-10 of FIG.9;

FIG. 1l is a fragmentary sectional View taken along lines 11--11 of FIG.9; and

FIG. 12 is an enlarged transverse sectional View taken along lines 12-12of FIG. 2.

Referring to FIGS. 1 and 2, the illustrated drilling device comprises ahammer motor, indicated generally by numeral 10, a rotation motor,indicated generally by numeral 12, and a chuck end construction,indicated generally by numeral 14. The shank portion 16 of a drillingrod is insertable into the chuck end 14 and is detachably securedtherein in a manner to be described. According to the invention, theshank 16 is impacted by the hammer motor 10 and is rotated by therotation motor 12 to provide an efficient rock cutting action for adrill bit (not shown) attached to the extreme outer end of the drillrod.

The cylinder 20 for the hammer motor 10 is provided with a longitudinalbore 22 which is closed at the rear by a cylinder head 24. A substantialportion of a cylinder sleeve 26 is disposed in the forward end of thecylinder bore 22 in coaxial relation therewith. An external ange 23formed near the forward end of cylinder sleeve 26 abuts the extremeforward end surface of cylinder 20; and, a forward portion 30 of sleeve26 extends outwardly of cylinder 20. The rear portion of a gene-rallycylindrical chuck housing member 32 coaxially surrounds portion 30 ofsleeve 26 and abuts flange 2S. The cylinder head 24, cylinder 20,cylinder sleeve 26 and chuck housing member 32 are held in theaforedescribed assembled relationship by the usual tie rods 34 and nuts36.

The rotation motor 12 is disposed in a two-part housing comprisingcasing member 4G and back head member 42 which are held in fluid-tightabutment by threaded fasteners 44 and cooperate to define a rotorchamber 46. At its forward end, the casing 40 is secured to the cylinderhead 24 in abutting relationship by threaded fasteners 48; and, thecasing 40 coacts with cylinder head 24 to define a gear chamber 50. Apair of gear-type rotors 52 and 54, best illustrated in FIG. 3, comprisethe operating elements of rotation motor 12 and are rotatably mounted inrotor chamber 46 for intermeshing engagement with one another. A shaft56, which comprises an integral extension of rotor 54, has formed on theforward surface thereof an integral pinion gear 57 which projectsforwardly into gear chamber 50, as shown in FIG. 4, for drivingengagement with a spur gear 60. Spur gear 60 is rotatably journaled ingear housing 50 and is provided with a forwardly extending, hollow hubportion 62 which is spaced for free rotation with respect to thesurrounding wall of an opening 64 through a boss 65 integrally formed oncylinder head 24. A drive shaft 66 is non-rotatably secured within thehub portion 62 of spur gear 60 by an intertting spline therebetween, andthe driveshaft 66 extends forwardly through opening 64 in parallel withand along the entire length of cylinder 2) into splined engagement witha small spur gear 68 which, as shown in FIG. 6, is rotatably journaledin a laterally projecting portion 33 of the chuck housing member 32. Asbest illustrated in FIG. 5, the small spur gear 68 is coupled to gearteeth 70 integrally formed about the exterior surface of andintermediate the ends of a generally tubular chuck driver 72 by an idlergear 74, shown in FIG. 6, which is rotatably mounted upon stub shaft 76in portion 33 of the chuck housing member 32. A chuck sleeve '7S isrotatable within a forwardly extending, reduced portion 35 of chuckhousing 32 and is non-rotatably connected to a forward extension 30 ofthe rotatable chuck driver 72 by an interlocking clutch jaw 82 formed onthe abutting surfaces of chuck sleeve 78 and extension 80. Alongitudinal bore through the chuck driver 72 is 4 divided into aforward portion 84 and a rear portion 36 by an internal annular frange88. A wear sleeve of hardened metal is disposed in the forward bore 84of chuck driver 72.

The aforementioned drill shank 16 is inserted through wear sleeve 90 andis held in chuck sleeve 78 in relative reciprocable, but non-rotatable,relationship by the usual connection therebetween afforded by lugs 17and interfitting recesses 92. The shank 16 and chuck sleeve 78 aredetachably held in proper assembly with respect to other parts of thechuck end of the drill by a cap 94 which is threadably secured t0 theforwardmost portion 35 of chuck housing 32.

The percussive motor or hammer motor 10 is of the well-known cxpansiblechamber type and generally comprises the rear portion of cylinder 20 anda sliding abutment provided by a reciprocating hammer piston, indicatedgenerally by numeral 96. The hammer 96 is provided with a cylindricalhead 98, having a close sliding fit with cylinder bore 22, and a flutedor splined shank 99 which penetrates a wear sleeve 100 and an internalange 102 of cylinder sleeve 26 and is received in the rearwardly openingbore S6 of chuck driver 72 in relatively reciprocable, but non-rotatablerelationship for a purpose to be described. The piston hammer 96reciprocates longitudinally within bore 22 and is provided with a powerstroke or down stroke and an exhaust stroke or return stroke by thevalvular action of a conventional distributing valve assembly 104disposed in `bore 22 in abutting relation with cylinder head 24. Thevalve 104 may be of any suitable construction and does not constitute anessential aspect of the present invention. A motive uid source (notshown) is connected to a hammer motor throttle valve 106, disposed incylinder head 24, by any suitable means such as fitting 108 and retainernut 110. As best shown in FIG. 7, the throttle valve 106 comprises avalve sleeve 112 rotatably mounted within a transverse bore 114. Theinterior of sleeve 112 is in communication with the aforementionedsource of motive fluid by means of fitting 108 and transverse bore 114.Valve sleeve 112 may be rotated within bore 114 by means of an operatorcontrolled handle 116 attached to a reduced end 118 of sleeve 112 whichprojects laterally from back head 24. As shown in FIG. 2, an opening 120in valve sleeve 112 may be radially alined with a fluid passage 122connecting the throttle valve bore 114 and a recess 124 which opensforwardly in cylinder head 24. The degree of alinement of opening 120and passage 122 is controllable by rotation of throttle handle 116 toselectively regulate the quantity of motive fluid flowing fromthrottlevalve bore 114, through opening 120 and passage 122 to recess124. Thus the throttle valve 106 may be fully open, fully closed orcontrolled to vary selectively the supply of m0- tive air to the hammermotor 10 for a purpose to be described. When throttle valve 106 isopened to supply motive air to distributing valve 104, the hammer 9Sreciprocates in response to the admission of motive fluid into cylinderbore 22 which acts upon piston head 98 to drive the hammer downwardlyand to lift the same upwardly in a regular cycle controlled bydistributing valve 104. In FIG. 2, the hammer 96 is shown in itslowermost position, or at the bottom of the power stroke. At this pointin the operational cycle of hammer motor 10, the end face 101 of hammershank 99 delivers an impact to the innermost end of drill shank 16. Thisimpact or hammer blow is transmitted through the drill rod to a drillbit (not shown) attached to the lower end of the rod to produce apercussive work cutting action.

FIG. 2 shows that a manually operable control valve, indicated generallyby numeral 130, for rotation motor 12 is disposed in the aforementionedbackhead member 42. In response to energization of rotation motor 12 bymeans of control valve 130, the drill shank 16 may be rotated to enhancethe aforementioned percussive cutting action of the drill rod. Moreparticularly, when the rotors 52 and 54 of motor 12 are caused tovrotate by introduction of motive fluid into motor chamber `46, inresp-onse to operation of control valve 130 in a manner to be describedmore fully hereinafter, the rotative drive of rotor 54 is mechanicallycoupled to the drill shank 16 through the previously described piniongear 57, spur gear 60, drive shaft 66, spur gear 68, idler gear '74,chuck driver 72, Iand chuck sleeve '78. The rotational `speed of theshank 16 with respect to that of the motor 12 is mechanically reduced intwo steps, that is, by the coaction of pinion gear 57 and a spur Igear60 and by the coaction of spur gear 68, idler gear 74 and the gear teeth70 formed lon the chuck driver 72'. Due to its relatively large lengthto diameter ratio, the drive shaft 66 provides a pretermined degree oftorsional flexing. During operation of the rotation motor, such flexingeffectively absorbs potentially damaging torsional strains inflictedupon the aforedescribed gears by sudden seizure of the drill rod in arock crevice or the like. To facilitate such torsional flexing lof shaft66, it is preferred that the shaft have a central longitudinal portion67 of reduced cross section interposed between the heavier splined ends69, 69 thereof.

An essential feature of the present invention is the provision of arotation motor, such as motor 12, which imparts bidirectional rotarymovement to a drill rod operatively connected thereto. This aspect ofthe invention has particularly utility as a means for coupling anduncoupling sectional drill rods which may be threadably attached to eachother and to a rotating shank member. Thus in drilling deep holes inrock, it is common practice to employ sectional drill rods which vary inlength from about two to .twenty feet. Such rod section-s are threadedat both ends `and may be made up into a string by use of threadedcouplings. Since it would be impractical to secure a threaded end of arod section in the driving chuck end of a drill motor, a speci-allyconstructed shank member, such as shank 16, may be provided with athreaded lower end (not shown) for connection to a section of threadedrod. This invention contemplates that the rotation motor l12 be employedin a novel manner to rotate shank y16 to facilitate aforementionedcoupling and uncoupling operations, thereby reducing the time andoperator effort required to accomplish this manually. To this end, thepresent invention provides mo'tor control valve 136 which is operable bythe drill operator to selectively reverse the direction of rotation ofshank 16. The structure of valve 130 is shown in detail in FIGS. 8through ll and generally comprises a transverse valve bore 132 throughbackhead 42 and a valve sleeve 134 disposed in bore 13-2 for rotation bya handle 136 threadably connected to the projecting end of 13S of sleeve134. As shown in FIG. 9, a pair `of spaced inlet ports 140, 142communicate between bore 132 and the interior of rotor chamber 46; and,a valve exhaust port 144 opens from bore 132 to the exterior of backhead 42. Valve sleeve 134 is provided with an axial bore 146 opening toone end thereof. A pair of spaced openings 148` and 150 intensect bore146 near its opposite ends to communicate the bore 146 to the valve bore132. An annular recess 152 formed intermediate the ends of sleeve 134opens outwardly therefrom for continuous communication with exhaust port144. Radially spaced arcurate recesses 154' and 156 extendinglongitudinally along the outer surface of sleeve 134 connected at theirrespective inner ends with ythe annular recess 152. A motive fluidsource (not shown) is connected to an enlarged threaded opening 133 ofbore 132 by a conventional fitting 158` and a retainer nut 160.

Assuming that valve sleeve 134-has been manually rotated to the positionshown in FIGS. 9, and 1l, motive fluid will -ow through fitting 158,into bore 146, through `opening 148 and inlet por-t 142 into rotorchamber 46. Referring 'to FIG. 3, it will be understood thatintroduction of pressure fluid into rotor chamber 46 through inlet port142 causes the intermeshing rotors 52 and 54 to operate as a gear motorand to rotate at variable speeds determined by the amount of pressurefluid admitted by valve into rotor chamber 46. The rotation motorexhaust is expelled `through inlet port 140, which in the assumedposition of valve 130i acts as a motor exhaust port, and flows through4recesses`154 and 152 to be expanded to atmosphere through valve exhaustport 144. The direction of rotation of rotors 52 and 54 may be reversedby rotating valve sleeve 134 to the position indicated by broken linesin FIGS. 10 and 1l, thereby to place sleeve bore 146 in communicationwith motor port 146 and to place motor port 142 in communication withthe arcuate recess 156 and valve exhaust port 144.

ln certain drilling applications, it may be desirable to place therotation motor 12 in a neutral or deenergized condition. This isaccomplished by rotating valve sleeve 134 to the position shown in FIG.8 where neither opening 148 nor opening 150 registers with motor inletports 140 and 142 to communicate pressure fluid to 'the rotor charnber46 in the aforedescribed manner. FIG. 8 also illustrates a spring-loadeddetent plunger 163 which is cooperable with radially spaced indentations(not shown) on the exterior surface of valve sleeve 134 to releasablyrestrain sleeve 134 in one of a number of preselected operativepositions with respect to valve bore 132.

From the foregoing detailed description of the structural Fandoperational features of the improved drilling device, it will beunderstood that great flexibility of control of the hammer motor 10l androtation motor 12 is provided. Thus, by selective operation of throttlevalve 106 and rotation control valve 131i, a drill operator canindependently control the percussive `and rotative action produced bymotors 10 and 12 to precisely regulate the rock cutting laction of adrill bit to meet a wide range of drilling requirements with greatefficiency. Moreover,- the rotation motor 12 provides 'the additionaladvantage of being -operable to couple and uncouple sectional drill rodswith great ease and speed.

Another aspect of this invention is provision of a rock drill of theaforedescribed construction, wherein the hammer piston 96 of thereciprocating motor 10 may be rotated with respect to the wall of thecylinder bore 22 by means of the independently rotated chuck ldriver 72.As previously described, the chuck driver 72 rotates in response tooperation of the rotation motor 12; and, the splined shank 99 of thehammer piston 96 is received in the rearwardly opening bore 86 of thechuck driver 72, as shown in FIG. 2. As illustrated in FIG. l2, theexterior of the reduced piston shank 99 is provided with a flutedsurface 160 which slidably interfits with a mating fluted surface 162formed on the interior of the chuck driver bore 86. The fluted surface162 is relatively short in length and is located near the rearmost endof the chuck driver '72. Preferably, the stroke of the hammer piston 96is such that the lmating surfaces 160i and 162 are in continuousinterlocking engagement as the piston shank 99 reciprocates relative tothe chuck driver 72. From the foregoing description, it will be apparentthat the hammer piston 96 and the chuck driver 72 are held in relativereciprocable, but non-rotatable, relation to each other by a splineconnection comprising the tluted surfaces 16? and 162. The importantadvantage afforded by this arrangement is that the piston hammer head 98is rotated as an incident to normal operation of the rotation motor 12of the drill. Therefore, localized wearing between the relativelysliding surfaces of the piston head 9S and the cylinder bore 22occassioned by slight manufacturing inaccuracies or misalignment of thehammer piston 96 Within the -cylinder bore 22 is greatly reduced, if noteliminated.

-In most rock drilling operations, compressed air or water is directedinto the drilled hole to flush rock particles to the surface. Commonly,the drill rod has a longitudinal bore and flushing fluid is conductedtherethrough to the bottom of the hole. Typically, a conduit or tube,such as tube 164 shown in FIG. 2, longitudinally penetrates the drillfrom its back head 42 and extends forwardly into the chuck end 14 wherethe tube is insertably received into the bore 166 of a drill rod or adrill shank. In the illustrated embodiment, the tube 164 coaxiallypenetrates the cylinder bore 22, the distributing valve 104, and thehammer piston 96 of the hammer motor 10. As best seen in FIGS. 2 and 3,the tube 164 is insertable through an .axial bore 168 in the rotor 54 ofthe rotation motor. The tube 164 is held in proper assembledrelationship by a plug 170 threaded into an opening 172 in the back head42. Plug 170 abuts the dared rear end 174 of the tube 164 and pressesthe same forwardly into fluid-tight engagement with an annular ealingbody 176 disposed about the tube. As Ibest illustrated in FIG. 8, asource of ushing fluid (not shown) is connected to a laterally openingrecess 17S in the backhead 42 by means of a conduit 180 and threadedfittings 12 and 184. Flushing iluid flows from the recess 178 throughthe opening 186 and then through the intersecting passages 188 relievedin the forward end surface of a reduced end 17S of plug 170.

An important feature of the present invention comprises theaforedescribed arrangement of the tube 164 with respect to the rotationmotor 12. As previously described, the tube 164 passes directly throughthe rotor 54 of the rotation motor 12; therefore, the rotor 54 and theentire rotation motor 12 may be substantially axially aligned with thehammer motor in end to end relationship. This is in contradistinction toknown arrangements of independent rotation motors and hammer motorswherein the rotation motor is typically mounted in laterally otfsetrelation to lthe hammer motor in order to avoid interference between themotor rotors and the uid conducting tube. The principal advantages ofthe arrangement disclosed by this invention are the compactness andsimplicity of construction made possible by end to end mounting of therotation motor and hammer motor. Moreover, the resulting reduction inthe required size and weight of the housing elements for the rotationmotor 12 permit increased ease in handling and mounting the entire drillassembly.

While the drilling device shown herein has been described as beingmanually operable by the valve handles 116 and 136, it will beappreciated that the throttle valve 166 and the rotation control valve130 may be modified, according to conventional practice, for operatorcontrol from a point remote from the drill itself. Moreover, it will beunderstood that the above description and accompanying drawingscomprehend only a general and preferred embodiment of the improveddrilling device and that various changes in construction, proportion andarrangement of the elements thereof may be made without sacrificing anyof the above-enumerated advantages of the invention.

Having fully described the invention, what is claimed as new and usefulis:

1. In a percussive drilling device; a huid-actuated hammer motorincluding a cylinder and a reciprocating piston hammer; `a housingattached to one end of said cylinder; a fluid-actuated, reversiblerotary motor disposed in said housing; chuck means rotatably disposed atthe other end of said cylinder for releasably retaining a tool thereinin impacting relationship with said piston hammer; driving meansinterposedbetween said rotary motor and said chuck means and operable torotate said chuck means in response to rotation of said rotary motor;said driving means including a shaft having a relatively large length todiameter ratio whereby said shaft is provided a predetermined degree oftorsional exibility; and, independently operable yfluid control valvesfor the respective motors whereby said chuck means and said pistonhammer may be operated selectively to provide both tool impacting andreversible tool rotation, tool impacting only, and reversible toolrotation only.

2. A device for actuating a rock drilling tool comprising a pressurefluid-actuated percussive motor operable to impact said tool; a pressureHuid-actuated rotary driving motor independent of ythe first mentionedmotor and operable to rotate said tool bidirectionally; control meansfor said percussive motor and said rotary motor comprising independentpressure iiuid valves selectively operable for electing tool impactingwithout tool rotation, bidirectional tool rotation without toolimpacting, and tool impacting with bidirectional tool rotation; and,said Valve for said rotary driving means having opposed operatingpositions for eifecting reversible tool rotation and a neutral position.

3. In a percussive drilling device; a Huid-actuated hammer motorincluding a cylinder and a reciprocating piston hammer; a housingattached to one end of said cylinder; a fluid-actuated, reversiblerotary motor disposed in said housing; chuck means rotatably disposed atthe other end `of said cylinder for releasably retaining a tool thereinin impacting relationship with said piston hammer; driving meansinterposed between said rotary motor and said chuck means and operableto rotate said chuck means in response to rotation of said rotary motor;said driving means including a shaft having a relatively large length todiameter ratio whereby `said shaft is provided a predetermined degree oftorsional flexibility; independently operable fluid control valves forthe respective motors whereby said chuck means and said piston hammermay be operated selectively to provide both tool impacting andreversible tool rotation, tool impacting only, and reversible toolrotation only; said fluid control valve for said rotary motor havingopposed operating positions for effecting reversible tool rotation and aneutral position.

References Cited in the tile of this patent UNITED STATES PATENTS1,408,684 Bayles et al Mar. 7, 1922 1,452,581 Welch Apr. 24, 19231,488,538 Hansen Apr. 1, 1924 1,538,421 Clark May 19, 1925 1,572,371Smith Feb. 29, 1926 1,773,366 Lear Aug. 19, 1930 1,807,839 Gartin June2, 1931 2,051,053 Morris Aug. 18, 1936 2,154,445 Gartin Apr. 18, 19393,044,448 Curtis et al July 17, 1962 FOREIGN PATENTS 1,231,192 FranceSept. 27, 1960

1. IN A PERCUSSIVE DRILLING DEVICE; A FLUID-ACTUATED HAMMER MOTORINCLUDING A CYLINDER AND A RECIPROCATING PISTON HAMMER; A HOUSINGATTACHED TO ONE END OF SAID CYLINDER; A FLUID-ACTUATED, REVERSIBLEROTARY MOTOR DISPOSED IN SAID HOUSING; CHUCK MEANS ROTATABLY DISPOSED ATTHE OTHER END OF SAID CYLINDER FOR RELEASABLY RETAINING A TOOL THEREININ IMPACTING RELATIONSHIP WITH SAID PISTON HAMMER; DRIVING MEANSINTERPOSED BETWEEN SAID ROTARY MOTOR AND SAID CHUCK MEANS AND OPERABLETO ROTATE SAID CHUCK MEANS IN RESPONSE TO ROTATION OF SAID ROTARY MOTOR;SAID DRIVING MEANS INCLUDING A SHAFT HAVING A RELATIVELY LARGE LENGTH TODIAMETER RATIO WHEREBY SAID SHAFT IS PROVIDED A PREDETERMINED DEGREE OFTORSIONAL FLEXIBILITY; AND, INDEPENDENTLY OPERABLE FLUID CONTROL VALVESFOR THE RESPECTIVE MOTORS WHEREBY SAID CHUCK MEANS AND SAID PISTONHAMMER MAY BE OPERATED SELECTIVELY TO PROVIDE BOTH TOOL IMPACTING ANDREVERSIBLE TOOL ROTATION, TOOL IMPACTING ONLY, AND REVERSIBLE TOOLROTATION ONLY.